Categorizing weight growth of infants born before 32 weeks’ gestation using the 2023 postnatal growth charts for preterm infants

To categorize growth and correlate growth categories with morbidities in infants born before 32 weeks of gestation. This retrospective study categorized weight growth by correlating mean growth velocity (GV) with growth trajectory z-score changes ( ΔGTZ ), as measured using 2023 Postnatal Growth Charts for Preterm Infants. The associations between weight categories and morbidities were assessed. Weight gain of infants without morbidities was categorized into three groups based on correlating ΔGTZ with mean GV: slower ( ΔGTZ < -0.1), in-parallel ( ΔGTZ -0.1 to 0.3), and faster ( ΔGTZ > 0.3). The proportions of infants with and without morbidities in these categories were evaluated across two distinct cohorts, revealing similar patterns. Both slower and faster growth were associated with bronchopulmonary dysplasia, while only slower growth was associated with retinopathy of prematurity. Using the 2023 Postnatal Growth Charts for Preterm Infants, this study presents an alternative method for weight growth categorization.